Chemical sampling of the eastern Scotia Sea
lization of ammonium and nitrate during austral summer in the Scotia Sea. Holm-Hansen, 0., and Foster, T. D. 1981. A multidisciplinary study of the eastern Scotia Sea, Antarctic Journal of the U.S., 16(5). Kils, U. 1979. Swimming speed and escape capacity of antarctic krill, Euphausia superba. Meeresforsch, 27, 264-266. Macaulay, M. Distribution and abundance of krill in the Scotia Sea as
Chemical sampling of the eastern Scotia Sea ROBERT L. MICHEL
Scripps Institution of Oceanography University of California La Jolla, California 92093
On leg 1 of the Scotia Sea expedition, samples were collected for analysis of nutrients, tritium, and carbon-14. Nutrients were collected at all odd-numbered stations at eight depths (5, 50, 100, 200, 300, 500, 750, and 1,000 meters). Tritium profiles were collected at stations 1, 7, 11, 15, 29, 33, 37, 43, 47, 55, 71, and 79; 12 samples were collected at each station (one at each of 12 depths-5, 25, 50, 75, 100, 150, 200, 300, 400, 500, 750, and 1,000 meters). Results from samples analyzed from station 1 are reported in the table. One precipitation sample was collected at station 28; it had a tritium concentration of 9.8 + 0.4 i'u (1 ni equals 1 tritium atom per 1018 hydrogen atoms). Tritium stations were chosen to encompass the water masses on each side of the convergence as well as in the convergence. Upwelling tends to lower tritium concentrations throughout the water column, while overturn adds tritium to the deeper layers. We expect our sampling series to clarify the importance of these two processes in the convergence. Samples of dissolved inorganic carbonate in surface waters were collected at approximately every third station and extracted by the method outlined by Williams and Linick
Concentration of tritium units as a function of depth In the Scotia Sea, station 1, 24 January 1981 Depth (in meters)
TUa
5 25 50 100 150 200 300 400
0.47 0.43 0.44 0.32 0.25 0.25 0.29 0.16
a Qne TU equals 1 tritium atom per 1018 hydrogen atoms.
170
observed acoustically, 1981. Antarctic Journal of the U.S., 16(5). McCarthy, J . J . , Taylor, W. R., and Taft, J. L. 1977. Nitrogenous nutrition of the plankton in the Chesapeake Bay. I. Nutrient availability and phytoplankton preferences. Limnology and Oceanography, 22, 996-1011. Olson, R. J. 1980. Nitrate and ammonium uptake in antarctic waters. Limnology and Oceanography, 25, 1064-1074.
(1975). These samples are being returned to the Mount Soledad Radiocarbon Laboratory to be analyzed for carbon-14. Sampling programs in the early 1970's had shown a significant difference in the surface carbon-14 concentrations of Weddell Sea waters and those of the Drake Passage (Ostlund et al. 1976; Weiss, Ostlund, and Craig 1979). Sections across the confluence should indicate whether this difference still exists. Biological samples were also collected for carbon-14 analysis from selected net tows. Samples of krill were obtained from stations 74, 94, 95, and 100. A phytoplankton sample was collected from station 95. Biomass such as krill should have a carbon-14 content representative of the waters in which they feed. Assuming a difference in carbon-14 between Weddell and Scotia Sea waters, we should be able to observe whether the krill we collected are long-term residents of the water masses in which they were found or migrants from the other side of the convergence. During the 1980 International Weddell Sea Oceanographic Expedition, two krill samples were collected for carbon-14 analysis (Foster et al. 1980). Both apparently were living in Weddell Sea water masses, and they had similar carbon-14 contents (station 80, 74°21.4'S 31°17.3'W, = —92 ± 6°/oo; station 130, 59°25.6'S 47(57.8'W, A14C = -96 ± 13%o, where A14 is the depletion inputs per mil of carbon-14 relative to pre-1950 atmospheric concentration in CO2). This program was supported by National Science Foundation grant DPP 79-21295. E. M. Druffel and T. W. Linick analyzed the carbon-14 samples, and T. L. Jackson was in charge of technical analysis of tritium samples. The sampling program was carried out by R. L. Michel and S. M. Griffin aboard the R/V Melville from 20 January to 20 February 1981. References Foster, T. D., Garrison, D. L., Michel, R. L., and Torresen, T. 1980. International Weddell Sea Oceanographic Expedition 1980. Antarctic Journal of the U.S., 15(5), 95-97. Ostlund, H. G., Brescher, R., Oleson, R., and Ferguson, M. J. 1976. Geosecs Atlantic radiocarbon and tritium results (Tritium Laboratory Data Report 5). Miami: University of Miami. Weiss, R. F., Ostlund, H. C., and Craig, H. 1979 Geochemical studies of the Weddell Sea. Deep-Sea Research, 26, 1093-1120. Williams, P. M., and Linick, T. W. 1975. Cycling of organic carbon in the ocean: Use of naturally occurring radiocarbon as a long and short term tracer. In Isotope ratios as pollutant source and behavior indicators. Vienna, Austria: International Atomic Energy Agency.
ANTARcTIC JOURNAL
Chemical sampling of the eastern Scotia Sea ROBERT L. MICHEL
Scripps Institution of Oceanography University of California La Jolla, California 92093
On leg 1 of the Scotia Sea expedition, samples were collected for analysis of nutrients, tritium, and carbon-14. Nutrients were collected at all odd-numbered stations at eight depths (5, 50, 100, 200, 300, 500, 750, and 1,000 meters). Tritium profiles were collected at stations 1, 7, 11, 15, 29, 33, 37, 43, 47, 55, 71, and 79; 12 samples were collected at each station (one at each of 12 depths-5, 25, 50, 75, 100, 150, 200, 300, 400, 500, 750, and 1,000 meters). Results from samples analyzed from station 1 are reported in the table. One precipitation sample was collected at station 28; it had a tritium concentration of 9.8 + 0.4 i'u (1 ni equals 1 tritium atom per 1018 hydrogen atoms). Tritium stations were chosen to encompass the water masses on each side of the convergence as well as in the convergence. Upwelling tends to lower tritium concentrations throughout the water column, while overturn adds tritium to the deeper layers. We expect our sampling series to clarify the importance of these two processes in the convergence. Samples of dissolved inorganic carbonate in surface waters were collected at approximately every third station and extracted by the method outlined by Williams and Linick
Concentration of tritium units as a function of depth In the Scotia Sea, station 1, 24 January 1981 Depth (in meters)
TUa
5 25 50 100 150 200 300 400
0.47 0.43 0.44 0.32 0.25 0.25 0.29 0.16
a Qne TU equals 1 tritium atom per 1018 hydrogen atoms.
170
observed acoustically, 1981. Antarctic Journal of the U.S., 16(5). McCarthy, J . J . , Taylor, W. R., and Taft, J. L. 1977. Nitrogenous nutrition of the plankton in the Chesapeake Bay. I. Nutrient availability and phytoplankton preferences. Limnology and Oceanography, 22, 996-1011. Olson, R. J. 1980. Nitrate and ammonium uptake in antarctic waters. Limnology and Oceanography, 25, 1064-1074.
(1975). These samples are being returned to the Mount Soledad Radiocarbon Laboratory to be analyzed for carbon-14. Sampling programs in the early 1970's had shown a significant difference in the surface carbon-14 concentrations of Weddell Sea waters and those of the Drake Passage (Ostlund et al. 1976; Weiss, Ostlund, and Craig 1979). Sections across the confluence should indicate whether this difference still exists. Biological samples were also collected for carbon-14 analysis from selected net tows. Samples of krill were obtained from stations 74, 94, 95, and 100. A phytoplankton sample was collected from station 95. Biomass such as krill should have a carbon-14 content representative of the waters in which they feed. Assuming a difference in carbon-14 between Weddell and Scotia Sea waters, we should be able to observe whether the krill we collected are long-term residents of the water masses in which they were found or migrants from the other side of the convergence. During the 1980 International Weddell Sea Oceanographic Expedition, two krill samples were collected for carbon-14 analysis (Foster et al. 1980). Both apparently were living in Weddell Sea water masses, and they had similar carbon-14 contents (station 80, 74°21.4'S 31°17.3'W, = —92 ± 6°/oo; station 130, 59°25.6'S 47(57.8'W, A14C = -96 ± 13%o, where A14 is the depletion inputs per mil of carbon-14 relative to pre-1950 atmospheric concentration in CO2). This program was supported by National Science Foundation grant DPP 79-21295. E. M. Druffel and T. W. Linick analyzed the carbon-14 samples, and T. L. Jackson was in charge of technical analysis of tritium samples. The sampling program was carried out by R. L. Michel and S. M. Griffin aboard the R/V Melville from 20 January to 20 February 1981. References Foster, T. D., Garrison, D. L., Michel, R. L., and Torresen, T. 1980. International Weddell Sea Oceanographic Expedition 1980. Antarctic Journal of the U.S., 15(5), 95-97. Ostlund, H. G., Brescher, R., Oleson, R., and Ferguson, M. J. 1976. Geosecs Atlantic radiocarbon and tritium results (Tritium Laboratory Data Report 5). Miami: University of Miami. Weiss, R. F., Ostlund, H. C., and Craig, H. 1979 Geochemical studies of the Weddell Sea. Deep-Sea Research, 26, 1093-1120. Williams, P. M., and Linick, T. W. 1975. Cycling of organic carbon in the ocean: Use of naturally occurring radiocarbon as a long and short term tracer. In Isotope ratios as pollutant source and behavior indicators. Vienna, Austria: International Atomic Energy Agency.
ANTARcTIC JOURNAL
